Screening machine



March 17.11925 H. s. MoNTGoMERY SCREENING CHINE Filed latch l5, 1923 3Sheets-Sheet 1 March 17. 1925. Y 1,530,193

H. S. MONTGOMERY S GREENING MACHT NE Filed March 15, 1923 3 Sheets-Sheet2 affory,

March 17, 1925. 1,530,193

H. S. MONTGOMERY SCREENTNG MACHTNE Filed March 15, 192:5 3 sheets-sheet5 fly. 7

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Patented Mar. 17, 1925.

lPATENT ol-.Flcs.

HENRY S. MONTGOMERY, OF RIVERSIDE, CALIFORNIA.

SCREENING MACHINE.

Application led March 15, 1923. Serial No. 625,223.

To all who/ml t may concern.'

Be it known that I, HENRY S. MONTGOM- ERY, acitizen of the UnitedStates, residing in Riverside, county of Riverside, State of California,have invented new and useful Improvements in Screening Machines, ofwhich the following is a specification.

This invention has to do with screens for screening and sizing materialsin general; and although the invention has been particularly developedwith referencer to the screening of fine materials that are of a lightand fluffy nature and therefore diiiicult to screen by ordinary methodsand some of.

the most advantageous features of the in vention are obtained whenscreening such materials, it will be understood that the invention isnot at all necessarily limited to use with such materials but may beapplied advantageously to the screening of any substance.

In the screening and sizing of such materials as diatomaceous orinfusorial earths A great dificulties have been encountered where it isdesired to screen to small size. The screens become quickly` clogged,even when mechanically vibrated; and the material has a tendency togather in balls that stand on the surface of the screen and effectuallyprevent screening-action. I have found that the rapplication of airpressure to the materials, in conjunction with mechanical screenvibration assists greatly in screening of such materials; and I havealso found that -if the materials, at the same time they are held downon the screen by air pressure, are moved over the surface of' thescreen, effective screening can be accomplished. In my prior andco-pending application entitled Method and apparatus for screeningmaterials filed Sept. 21, 1922,

p Serial No.' 589,518, I have set out a screening apparatus whichembodies these gen eral principles; and the present invention presentsimprovements in such an apparatus as set out in said prior application.The present application deals with various features of improvement thatwill be fully understood from the following specification, lsaidimprovements having mainly to do with the method of introducing air forthe purpose of creating the desired pressures and movements of thematerial, and with means for removing the over size from the screen fromtime to time. The improvements `also include certain mechanicalreinements, and also. mechanical arrangements for putting several suchscreens into combination with each other for the purpose of subjectingmaterial to several suc` cessive screenings. All of these things andvarious other objects and features of accomplishment of the invention,will be best understood from the following detailed description ofpreferred and specific forms of devices illustrative of the invention,reference for such purpose being had to the accompanying drawings inwhich-v Fig. 1 is a vertical central section showing a single unitmechanism in accordance with my invention;

Fig. 2 is a plan section of the same on line 2-2 of Fig. 1;

Fig. 3 is an enlarged detail section on line 3 3 of Fig. 2,

Fig. 4 .is an enlarged detail section on line 4--4 of Fig. 2;

Fig. 5 is a vertical central section showing a mechanism includingseveral screening units;

Fig. 6 is a central vertical section of a single `vunit mechanismshowing a modied kept moving over the surface of the screen; u

and although this motion over the surface o f the` screen may bepreferably circular, it is not necessarily so.

I illustrate at 10 a circular screen casing with a screen 11 in itsbottom, a delivery casing 12 extending below the screen casing toconnect with a collector 13 which may be in the form of a collector bag'or any other of the various collector arrangements that are well knownin the art. The upper end of screen casing 10 is closed by a cover plate14 and on this' cover plate a frame or other support 15 may be mountedto su port the bearings and stuffing boxes, ete., or the mechanism thatI am about to describe.

Within the screen casing there are two sets of radial tubes 16 and 17.Tubes 16 are those throu h which air under pressure is admitted tot escreen while tubes 17 are those tlnfoughgwhich, by the application ofsuction, the oversize is removed from the screen. The aii discharge fromtube 16 is through lines of perforations 18 that point diagonallydownwardly, so that the air discharge will force the material down ontothe screen and also move it around (over the surface of) the screen. Ishow several tubes 16; and, even if those tubes are stationary the airjets issuing from them will keep the material traveling over the,screen. But I prefer to rotate the tubes 16;--so as to make uniformtheir action over the whole surface of the screen. And when the tubesare rotated, the jet perforations may be pointed more nearly downwardlyor exactly downwardly, as the rotation may furnish the movement over thescreen. Or I may prefer in any case to point some perforations directlydownwardly and some diagonally downwardly. Likewise, I prefer to rotatethe suction tubes 17 in order to make their action uniform over thewhole screen surface. Accordingly, I mount the vacuum tubes 17, whichhave a slot or a line of perforations as shown at 19 along their lowersides. on and in communication with a vertical rotating tube 20 whichextends up through cover plate 14. through some suitable packingmeans asindicated at 21. The upper end of this tube 2O discharges into a chamber22 stationarily mounted on framing 15, a stuffing box being provided at'23 to make a suliiciently tight joint between the revolving tube and thechamber. A suction pipe 26 connects chamber 22 with a suction fan 25,under control of valve 24; and the fan may discharge into a collector 27of any suitable type.

Inside the tube 2.0 and rotating with it is an air pipe 28; and air jettubes 16, extending through the wall of tube 2D, connect with air pipe28. through tube 20 and chamber 22 and through al stuffing box 29, outof the chamber, and then has a swivel connection 30 of some suitablekind with an air pressure line 31.

The rotating system that I have described may be rotatedby the airreaction of jets This air pipe extends upI 18; but I may prefer also togive this rotating system a positive drive, as by motor M operating onWorm gear 32 on rotating tube 20. If a motor is used, the parts may berotated in either direction, either with or against the direction inwhich they would be rotated by air reaction.

The material to be screened may be fed into the device in differentmanners, for instance, it may be fed by the screw feed means indicated35 in Fig. 1; or it may be fed in by an air blower 36 that will blow thematerial through tube 37 tangentially into the screen easing. Thistangential introduction of the material, along with the air in which itis blown, will of course set up a circular or cyclonic motion of thematerial over the screen. But, regardless of the manner in which thematerial is introduced, movement of the material over the screen, inthis case, a circularl or cylonic movement, will be set up andmaintained by the action of the air jets. At the same time, the airintroduced by the air jets. and that introduced with the material, ifthe air form of feed is used, will set up in the screen casing above thescreen a certain air pressure above the air pressure that is maintainedbelow the screen. This air pressure tends to hold the material down onthe screen; and at the same time the air movement moves the materialover the surface of the screen. The air pressure, in addition to thedownward action of the air jets tends to keep the lines moving throughthe screen and keep the screen clean` while the movement of theparticles tends to break up any collections of particles so that theparticles themselves may pass through the screen. I may also apply asuction to discharge 13 to aid in takmg the lines away from the screen.

The Whole screen is mounted on a vibratory mounting. For instance, itmay be mounted on a frame 40 supported on springs 41; and any suitablemeans may he used to vibrate frame '40 and the screen. For instance,asmall air hammer. indicated at 42, may act to vibrate the system. It isnot necessary to have a violent vibration: it is only desired to havesuiiicient vibration to help materials pass through the screen and tohelp dislodge any oversize particles that might otherwise be stuck inthe screen.

When the device is in operation the niateriall is fed in to thevibrating screen at a suitable rate, and air pressure is admitted to airjet tubes 16 and those tubes may berevolved. The material is held downon the screen by the lair pressure and is thrown against the screen andalong its surface by the direct action of the air jets 18, so that thematerial is kept in constant motion over the surface of the screen andis brought into more or less forcible contact with the screen. Thefinesass through the screen and go to the collec or; and when theoversize ha-s accumulated on the screen the suction is turned on totubes 17 and they act to pick u the oversize and thus clean the screen.rdinarily, the applicatlon of the suction action through the eriod ofone revolution of tubes 17 is su cient to clean the screen. It is notnecessary to shut ofi' the feed of material or to shut off the air feedto tubes 16 during this suction' cleaning action, although that may bedone 1f desired; but in any case only a small amount of fines is carriedout with the oversize'. This oversize may, after passing throughcollector 27, be passed back tothe crusher or grinder, or it may be putinto storage bins.

To operate the suction periodically I may provide a simple automaticmeans to open valve 24 periodically; as a cam 60 operated by Worm gear.61 from revolving tube 28.

In Fi 6 I show a modification in which a propeller fan 50 may be used toprovide the air motion for carrying and pressing the materialagainstscreen 1-1 and for moving it over the surface of the screen. Thisfan 50, driven by Vany sutable'meansas by i pulley 51, creates an airmotionr downwardly and .circularly around over the screen; with the samegeneral effect and result as hereinbe-fore stated. lIt will beunderstood that in any case the air movement around (parallel with thesurface of) the screen is slow enough that the material is not blownover the screen surface so fast that it has no chance to go through thescreen.

In Fig. 5 'I show an yarrangement of the type of device of Fig. 1 tomake a mechanism including a number of screen units. Here I provide acomposite screen casing made up of sections -10 and 10 with superposedscreens 11, 11, and 11b which lnay be of increasing ineness. Here therotating tube 20 extends on down through the uppermost screen 11, whereit passes through a stuing box 60 and then through a suction chamber 61.Then the tube 2Q extends on down to and through the screen 11 where thesame construction is repeated. This arthere are screens in the multipleunit mechanism. At each chamber 61 the tube 20 has openings 62 throughits wall, and there is an internal plug 63 in tube 20 just above theseopenings. From each suction chamber 61 a suction pipe 26a extends to asuc` tion fan 25, By reason of the construction herein described it willbe seen that the uppermost suction fan 25 will draw only on theuppermost suction tubes 17; the next suction fan 25n will draw only onthe next suction tubes 17; while the lowermost suction fan 25a will drawonly on -the lowermost suction tubes 17.

All the tubes 16 are connected to the common air pressure pipe 28 whichextends the whole length of composite tube 20. Thus, while the variousair.

jet tubes 16 are fed from a common air supply., the several suctiontubes 17v connect with individual suction apparatus, and the oversizeremoved from the several screens is consequently kept separate. If thescreens are progressively finer, the oversize from all Y the,y screens,excepting possibly the uppermost one, will be definitely sized, and sothese oversizes may be passed to storage.

In Figs. 7 and 8 I show a different structure. Here the air jet pipes16":L are arranged in grid formation and are fed with airl from apressure connection 31'. The jets may polnt perpendicularly toward thescreen 11 as indicated. The jet pipes are moved back and forth in theirplane (parallel to the screen) by an eccentric and. connecting' rod 71attached to pivoted armv 72 connected to the grid of pipes; a. guide pin73 in slot 74 of the screen housing 10" guiding the grid of pipes in itsmovement. As the pi es are reciprocaled parallel to the' screenv thlsmovement furnishes the movement of the air jets parallel to the screento move the material over the screen. It will be understood that here,or in the other form if jet openings pointing `straight at the screenare used, the resultant of the air jet movement per se andthe movementof the pipes over the screen is to give an air jet that has a resultantmovement diagonally onto the screen; and that Where in the followingclaims I speak of means `to delivera diagonal air jet I mean to includeeither arrangement for getting such a. diagonal movement of air.

The screen is mounted on a spring supported vibrated frame as beforedescribed; and stands at a slight angle so that the` oversize workstoward the lower end where itv Having described a preferred form of 'myinvention, I claim rangement maybe repeated as many times as 1. Incombination, a screen, and'means to lfeed material onto it, and aplurality of over the screen, with the result of blowing the materialalong the screen and through 1t. 3. In combination, a screen, and meansto feed material onto it, and a plurality of means to direct 4air jetsdiagonally downwardly onto and along the screen at spaced points overits surface, said means being rotatable in a plane parallel to thescreen, with the result of blowing the material alon the screen andthrough it.

4.?[11 combination, a screen, and means to fee-d material onto it, and aplurality of means to direct air jets diagonally downwardly onto andalong the screen at s aced points over its surface, said means em odyinga plurality of radial perforated tubes rotating about a common center,and means to feed air pressure to the tubes, with the result of blowingthe material along the screen and through it.

5. In combination, a screen and means to lfeed material onto it, andsuction means operative over the screen to remove oversize material,embodying a suction tube movable over the screen surface with a suctionopening at its under side, and means to apply suction intermittently tothe tube.

6. In combination, a screen and means to feed material onto it, arevolving tube on an axis substantially perpendicular to the screen, aperforated suction tube mounted on and communicating with the revolvingtube and extending radially therefrom at a. point near the screen, meansto apply suction to the revolving tube, an air pressure pipe inside therevolving tube, and an air jet pipe mounted on the revolving tube andconnecting with the pipe.

7. In combination, a screen and means to feed material onto it, arevolving tube on an axis substantially perpendicular to the screen, aperforated suction tube mounted on and communicating with the revolvingtube and extending radially therefrom at a point near the screen, meansto apply suction to the revolving tube, an air pressure pipe inside therevolving tube, and an air jet pipe mounted on the ,revolving tube andconnecting with the pipe, said air jet pipe having jet perforations thatpoint diagonally downwardly to deliver air jets down onto and along thescreen.

S. In combination, a screen and means to feed material onto it, arevolving tube on an axis substantially perpendicular to the screen, aperforated suction tube mountedthe revolving tube and connecting withthe pipe, each air jet pipe having jet perforations that pointdiagonally downwardly to deliver air jets down onto and along thescreen.

9. In combination, a screen and means to feed material onto it, arevolving tube on an axis substantially perpendicular to the screen, aperforated suction tube mounted on and communicating with the revolvingtube and extending radially therefrom at a point near the screen, meansto apply suction to the revolving tube, an air pressure pipe inside therevolving tube, and an air jet pipe mounted on the revolving tube andconnecting with the pipe 5 and means positively to rotate the revolvingtube.

10. In combination, a screen and means to feed material onto it, arevolving tube on an axis substantially perpendicular to the screen, aperforated suction tube mounted on and communicating with the revolvingtube and extending radially therefrom at a point near the screen, meansto apply suction to the revolving tube, an air pressure pipe inside therevolving tube, and a plurality of radial air jet pipes mounted on therevolving tube and connecting with the pipe, each air jet pipe havingjet perforations that point diagonally downwardly to deliver air jetsdown onto and along the screen, and means positively to rotate therevolvlng tube.

11. In combination, a screen and means to feed material onto it, meansto vibrate the screen, means to create an air current over and along thescreen, and means to apply suction over the screen .to remove oversizematerial.

12. In combination, a screen and means to feed material onto it, meansto vibrate the screen, means to create a circular air current over thescreen, and revolving means to apply suction over the screen to removethe oversize material.

13. In combination, a screen and means to feed material onto it, meansto vibrate the screen, means to create a circular air current over thescreen, and revolving means to apply suction over the screen to removethe oversize material, the means for feeding material onto the screeninvolving an air current feed tangential of the screen.

14. In combination, a screen and means to feed material onto it, suctionmeans operative over the screen to remove oversize material, and meansto apply suction intermittently to said suction means.

15. In combination, a screen and means to feed material onto it, arevolving tube on an axis substantially perpendicular to the screen,another tube within the revolving tube, radially extending tubes overthe screen and connected with the inner and outer perpendicular tubes,respectively,'one of said radial tubes being perforated for applcationof suction action to the screen and lll) the other having jet openingsdirected at the screen, and means to app y suction and air pressure,respectively, to the two per- Pendicular tubes.

16. In combination, a screen and means to feed material onto it, andmeans, independent of the material feeding means to direct an air jetdiagonally downwardly onto and along the surface of the screen, with thevresult of blowing the material along 10 the screen and through 1t.

`In witness that I claim the foregoin I have hereunto subscribed my namethis th day of March, 1923.

` HENRY S. MONTGOMERY.

